Thirteen people died when a Mexican military helicopter crashed Friday during a tour of earthquake damage in Oaxaca state.

The chopper was carrying Mexico's interior minister, Alfonso Navarrete Prida, and Oaxaca Governor Alejandro Murat, who were injured along with more than a dozen others. The state attorney general's office said both men suffered only "slight concussions."

In the same statement, the attorney general's office said 12 people died at the scene of the crash in Santiago Jamiltepec, and a 13th person died at a hospital afterward. Three of the dead were reported to be children.

Mexican President Enrique Pena Nieto has issued a statement via social media about the accident. He said it took place while the helicopter was landing.

Pena Nieto tweeted, "Unfortunately, people on the ground lost their lives and others were wounded. My condolences to their families and my wishes for a prompt recovery to those injured."

The president said none of the fatalities were due to the earthquake or aftershocks that hit southern Mexico on Friday.

The U.S. Geological Survey put the quake's magnitude at 7.2 and said its epicenter was a rural area of southern Oaxaca state near the Pacific coast and the border with Guerrero state.

Officials in Oaxaca say there was superficial damage to some buildings and that about a million homes and businesses lost power. The state government said shelters have been opened for those fleeing damaged homes.

In Mexico City, residents felt sustained shaking for about a minute, with tall buildings swaying and cracks appearing in the plaster of older structures.

Both Mexico City and the south of Mexico are still recovering from earthquakes in September that caused widespread damage.

Residents in Mexico City flooded into the streets Friday, fearing a repeat of the strong September quake, but there were no signs of major damage.